1. Field of the Invention
This invention relates generally to orthotics and more particularly to an ankle foot orthosis for remediation of foot drop symptoms.
2. Antecedents of the Invention
Foot drop, drop foot and foot dangle are terms which have been employed to describe ankle and toe dorsiflexor paresis resulting in the inability to raise the foot at the ankle, such that the foot inclines toward and scrapes the ground when walking.
The etiology of foot drop may be traced to a plurality of factors including neurological, e.g. peroneal nerve damage, muscular, e.g. dorsiflexor injury and anatomic dysfunction, as well as combinations thereof.
A common remediation technique for foot drop involved the employment of an ankle foot orthosis. These devices were costly and often required professional fitting and customized shoes. Professional fitting procedures of some devices required the taking of impressions of the affected foot. There were significant delays between the fitting and receipt of the customized orthosis.
Some devices were configured to completely lock the ankle joint and constrained normal ankle joint motion in ranges other than dorsiflexion, resulting in discomfort and restricted gait. Discomfort was also associated with those ankle foot orthoses which included components inserted into the shoe itself.
Prior ankle foot orthoses also included components which surrounded the calf or ankle to support the affected foot and often caused irritation of the ankle or calf and muscle strain.
Generally, prior ankle foot orthoses were unsightly, which detracted from the beneficial results which might have been achieved in alleviating steppage gait.